This invention relates to a device for plugging the interior of a pipe having an internal cylindrical surface. The pipe is provided with an access opening with a diameter which may be substantially equal to or smaller than the diameter of the pipe internal cylindrical surface.
Devices exist for forming an opening in the wall of a pipeline even while the pipeline is under liquid or gas pressure. For references to devices that can be used for tapping a pipeline while under pressure, see the following U.S. patents: U.S. Pat. No. 3,614,252 entitled "Tapping Apparatus"; U.S. Pat. No. 4,579,484 entitled "Underwater Tapping Machine"; and U.S. Pat. No. 4,880,028 entitled "Completion Machine". These previously issued patents are incorporated herein by reference.
In order to terminate the flow through a portion of a pipeline that is under liquid or gas pressure after it has been tapped by a tapping machine as referred to in the above-referenced patents, it is frequently necessary to plug the interior of the pipeline. Normally, in laying out a piping system, valves are installed in the pipeline where it will be necessary to stop or regulate the flow of liquids or gases through the pipeline, but in many instances, it becomes necessary to terminate flow in a portion of a length of a pipeline that does not have a valve previously installed for that purpose. The present invention is directed to a device for performing this service. Others have previously suggested plugging devices for plugging the interior of a pipeline through an opening formed in the wall of the pipeline. For background reference to pipe pluggers, see the following U.S. patents which are incorporated herein by reference: U.S. Pat. No. 3,665,966 entitled "Pipe Plugger" issued May 30, 1972 and U.S. Pat. No. 3,626,475 entitled "High Temperature Pipe-Plugging Apparatus" issued Dec. 7, 1971.
The present disclosure relates to improvements in a pipe plugging device. The improvements to be described are particularly important in plugging the interior of a pipe that is under substantial liquid or gas pressure.